NEW YORK -- The Port Authority of New York and New Jersey blamed construction delays for pushing back the opening date of the World Trade Center memorial to 2011.

New York Gov. George Pataki said the World Trade Center memorial would open to the public on Sept. 11, 2009, but Port Authority officials said construction is slated for a 2011 completion date, The New York Times said Wednesday.

Port Authority officials said the steel framework for the plaza is set for a 2009 completion, but the memorial plaza and museum may not see completion until 2011.

The memorial plaza is set to feature groves of white oaks and gum trees surrounding two square chasms meant to symbolize the twin towers in addition to a below-ground museum.

Anthony E. Shorris, executive director of the Port Authority, said timetable revisions are ongoing, but hope for meeting the original deadline still loomed.

"We'll obviously do our best to bring it back if we can," he said, "but we wanted to put out the most realistic schedule we could, and right now the full completion of everything is looking more like '11 than '10."

The Port Authority Tuesday also delayed a vote on a deal with Westfield Group, which plans to develop retail space in the area, the Times said.